🔒 refactor(bots): remove !login command and enforce OIDC-only auth

- Remove !login and !logout commands from all 16+ Matrix bots
- Remove login/logout references from all help/welcome messages
- Disable password login in Synapse (password_config.enabled: false)
- System is now OIDC-only via Mana Core authentication

Users must authenticate via "Sign in with Mana Core" in Element.
Existing bot access tokens remain valid.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

services/matrix-mana-bot/src/config/configuration.ts

@@ -37,11 +37,6 @@ export default () => ({
 // Help text for the unified bot
 export const HELP_TEXT = `**🤖 Mana - Dein Assistent**
 
-**👤 Account**
-• \`!login email passwort\` - Anmelden
-• \`!logout\` - Abmelden
-• \`!status\` - Account & Bot Status
-
 **AI & Chat**
 Schreib einfach eine Nachricht - ich antworte!
 • \`!model [name]\` - KI-Modell wechseln